Baseball & Softball Batting Swing Trainer and Hitting Training Aid The lightweight plastic cup easily attaches to any bat in seconds. The Line Drive Pro Swing Trainer forces the hitter to swing through the hitting zone properly to launch the practice ball and get the desired outcome. The patented batting trainer forces hitters to USE proper swing mechanics. Players will instantly FEEL proper swing mechanics and SEE where the ball is going. The baseball and softball training aid provides instant visual feedback and reinforces a short, compact swing. It develops barrel control and continued use of the product will TRAIN muscles to repeat the proper FEEL of keeping the barrel in the zone. A great softball / baseball swing trainer for all ages and skill levels. Small and lightweight design goes anywhere Includes 3 practice tennis balls, mesh bag and velcro straps. Not for use with real baseballs or softballs - for use with lightweight balls / tennis balls.